unfortunately they do not work

Probably you need to make some clean in your plugin folder. Keep only ONE version and the LAST.
1. I suggest you to install Plugins manager from here or here .
2. Depend of your OS.
The SH3D is installed under eteks folder. There you have sweethome3d folder with other folders and files.
Backup (copy) the sweethome3d folder on other place(eventually on a portable stick).
On the new computer, after the SH3D installation and first run, you have to find the sweethome3d folder and overwrite with the previous folder.